Various processes can be used to form articles from plastic, including bottles and other containers. The plastic articles can generally be formed at a single site with plastic resin pellets brought to a molding machine and a finished product being removed from the molding machine. In one process, a supply of plastic pellets is maintained in a silo, is blended with other materials, such as color and additives, and is delivered to a material hopper of an extruder wherein the blended materials are melted and mixed so that they are ready for injection into a mold. The melted material is injected into a mold and is cured slightly to form a parison. The parison is then transferred to a blow mold wherein pressurized air is used to mold the parison within the mold cavity. After being molded, the bottles can be flame treated, inspected for leaks or imperfections in the threads or panels, and then packaged with other containers for shipment.
Typically, the various portions of the machine, for example, the extruder, the parison mold, and the blow mold are controlled by a suitable electronic controller, and monitored by an operator of the machine and controller. To ensure quality of the containers being molded, machine operators manually remove samples from the production line at prescribed intervals, inspect the sample bottles, and record the information obtained from the inspection. Both the machine operators and the inspectors are usually required to complete compliance paperwork for various parameters of the manufacturing process and sampled containers indicating that these were within predetermined limits. After all of the compliance paperwork is completed and corrected, a certificate of compliance can be generated for the particular lot or production run of bottles. Changes to the operational parameters of the machine are done by the machine operator in response to information provided by the controller indicting that the machine is operating outside of predetermined limits, or in response to information obtained from sample bottle inspection indicating that the inspected bottle parameters are outside of predetermined quality limits.